Apparatus for fabricating wood structures

ABSTRACT

Apparatus for fabricating wood trusses of the type having lower chord members, upper chord members and web members extending from the lower chord members to the upper chord members. The apparatus comprises two presses each having an upper and a lower platen which are relatively movable toward and away from one another for driving nailing plates into two or more of the wood members of a truss from above and below, and means for supporting the wood members which are to be joined together by the nailing plates, the supporting means including a plurality of supports and means cantilevered relative to each support for holding wood members with clearance therebelow. One of the presses is mounted on a carriage adjacent the upper chord and the other press is mounted on a carriage adjacent the lower chord for movement of each press along its respective chord into an operating position at a first support for driving nailing plates into the wood members, and for movement in a generally lateral direction with respect to the press sidewise out of its operating position at the first support and into its operating position at a next successive support along its respective chord. Each press carriage is movable along its respective chord independently of the other, and has means for controlling movement thereof including means movable therewith for sensing the approach of its press to its operating position at a support in advance of its arrival at its operating position thereby to initiate deceleration of the carriage and for sensing the arrival of the press at its operating position at the last-said support so as to stop movement of the press carriage with its press at its operating position for driving nailing plates into the wood members.

United States Patent [191 Moehlenpah Feb. 18, 1975 1 APPARATUS FORFABRICATING WOOD STRUCTURES [76] lnventor: Walter G. Moehlenpah, 9906Old Warson Rd., Ladue, Mo. 63124 [22] Filed: Jan. 4, 1973 [21] Appl.No.: 320,900

Moehlenpah et t l00/DlG. 13 Jureit l00/DlG. 13

Primary Examiner-Billy J. Wilhite Attorney, Agent, or Firml(oenig,Senniger, Powers and Leavitt ABSTRACT Apparatus for fabricating woodtrusses of the type having lower chord members, upper chord members andweb members extending from the lower chord members to the upper chordmembers. The apparatus comprises two presses each having an upper and alower platen which are relatively movable toward and away from oneanother for driving nailing plates into two or more of the wood membersof a truss from above and below, and means for supporting the woodmembers which are to be joined together by the nailing plates, thesupporting means including a plurality of supports and meanscantilevered relative to each support for holding wood members withclearance therebelow. One of the presses is mounted on a carriageadjacent the upper chord and the other press is mounted on a carriageadjacent the lower chord for movement of each press along its respectivechord into an operating position at a first support for driving nailingplates into the wood members, and for movement in a generally lateraldirection with respect to the press sidewise out of its operatingposition at the first support and into its operating position at a nextsuccessive support along its respective chord, Each press carriage ismovable along its respective chord independently of the other, and hasmeans for controlling movcment thereof including means movable therewithfor sensing the approach of its press to its operating position at asupport in advance of its arrival at its operating position thereby toinitiate deceleration of the carriage and for sensing the arrival of thepress at its operating position at the last-said support so as to stopmovement of the press carriage with its press at its operating positionfor driving nailing plates into the wood members.

34 Claims, 13 Drawing Figures PATENIED FEB I 8i975 SHEEI 30F 9 m OEmgmgnnmsms 71.866530 saw u m 9 FEG.5

PATENIEDFEH I 81975 SHEET 5 OF 9 FIG.IO-

PATENTEDFEB I 81975 SHEET 8 OF 9 FlG.7

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PATEHTED FEB I 8 I975 sum 70F 9 mi LY APPARATUS FOR FABRICATING WOODSTRUCTURES BACKGROUND OF THE INVENTION This invention relates toapparatus for fabricating wood structures, and is more particularlyconcerned with apparatus for fabricating shallow depth (e.g., 12-36inches) flat trusses for use as floor joists and the like.

In conventional construction practice, solid wood members, such as 2 X12s, are used for floor joists. However, due to increased lumber costsand scarcity of long span lumber of the required dimensions, flattrusses made of less expensive lumber (e.g., 2 X 4s) are becomingincreasingly popular for use of floor joists in place of solid woodjoists. In addition to utilizing less expensive lumber, trusses arelighter weight and permit considerable labor savings because electricalwiring, plumbing, and ventilation ducts may easily be routed throughopenings in the truss and thus provide an unobstructed surface at thetop and bottom of the trusses to which ceiling or subfloor sheathing,such as wallboard or plywood, may readily be nailed.

While flat roof trusses have been fabricated by apparatus such as shownin my US. Pat. No. 3,693,542, the fabrication of flat floor trussespresents special problems that render many types of roof trussfabricating apparatus unsuitable for floor truss fabrication. Moreparticularly, the relatively shallow depth of floor trusses (forexample, floor truss depths may range from 12-36 inches while roof trussdepths may range up to 15 feet) require that the apparatus mustaccommodate trusses of such shallow depth and yet be sufficientlyadjustable to support the wood members at the joints of the truss to beformed with the position of the joints varying, depending on theparticular truss to be formed. The apparatus of this invention isespecially adapted to fabricate shallow depth, flat floor trusses in arapid and efficient manner at relatively low cost.

SUMMARY OF THE INVENTION Among the several objects of this invention maybe noted the provision of apparatus for fabricating shallow depth, flatfloor trusses which is adjustable to accommodate trusses of variousdepths, lengths and configurations; the provision of such apparatuswhich requires a minimum of floor space; the provision of such apparatuswhich enables workmen to lay the wood members on a portion of theapparatus to form a first truss while the wood members of a second trusson another portion of the apparatus are being secured together therebyto enable rapid and economical fabrication of trusses; the provision ofsuch apparatus which operates automatically to secure the wood membersafter they have been properly placed in the apparatus; the provision ofsuch apparatus which lifts a completed truss to facilitate removal ofthe truss; and the provision of such apparatus which is of ruggedconstruction and relatively low cost. Other objects and features of thisinvention will be in part apparent and in part pointed out hereinafter.

Briefly, apparatus of this invention for fabricating wood trusses of thetype having lower chord members, upper chord members and web membersextending from the lower chord members to the upper chorrl memberscomprises two presses each having an upper and a lower platen which arerelatively movable toward and away from one another for driving nailingplates into two or more of the wood members of a truss from above andbelow, means for supporting the wood members which are to be joinedtogether by the nailing plates, this supporting means including aplurality of supports and means cantilevered relative to each supportfor holding wood members with clearance therebelow. The apparatus alsoincludes means mounting one of the presses adjacent the upper chord andmeans mounting the other press adjacent the lower chord for movement ofeach press along its respective chord into an operating position at afirst support for driving nailing plates into the wood members, and formovement in a generally lateral direction with respect to the presssidewise out of its operating position at said first support and intoits operating position at a next successive support along its respectivechord. Each press is movable along its respective chord independently ofthe other, and means is provided for controlling movement of each of thepress mounting means including means movable therewith for sensing theapproach of the press to its operating position at a support in advanceof its arrival at its operating position thereby to initiatedeceleration of the mounting means and for sensing the arrival of thepress at its operating position at the lastsaid support so as to stopmovement of the press at its operating position for driving nailingplates into the wood members.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of apparatus ofthisinvention having two frames arranged end-to-end, each frame holdingwood members which are to be secured together to form a floor truss;

FIG. 2 (sheet 2) is a partial perspective of one of the framessupporting wood members and showing a pair of presses movable along theupper and lower chords of the truss for driving nailing plates into thewood members;

FIG. 3 (sheet 6) is an enlarged plan view of one of the frames of FIG.1;

FIG. 4 is a front elevational view of the frame of FIG.

FIG. 5 is an enlarged vertical section on line 5--5 of FIG. 4;

FIG. 6 is an enlarged partial perspective of one of the frames showingmeans for lifting a completed truss clear of the supports to facilitateremoval of the completed truss;

FIG. 7 is an enlarged side elevation of the truss lifting means; FIG. 8is an enlarged view taken on line 8-'8 of FIG. 3 of one of the supports;

FIG. 9 is an enlarged partial plan view taken on line 9-9 of FIG. 4illustrating means for clamping the wood members in position for beingsecured together by nailing plates;

FIG. 10 is a side elevation of a press carriage;

FIG. 11 is a block diagram of means for controlling operation of thepress and press carriage; and

FIGS. 12 and 13 are electrical schematics of means for controllingoperation of the apparatus.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,apparatus of this invention, indicated in its entirety at I, is shown inFIG. 1 for fabricating wood trusses T of the type having lower chordmembers LC, upper chord members UC and web members W extending from thelower chord members to the upper chord members. More particularly,apparatus of this invention is especially useful for fabricating flat,shallow-depth trusses made of 2 X 4 commercially available lumber foruse as floor joists. The trusses shown in the drawings have ductopenings DO formed at the midpoint of the truss to permit ventilatingducts to be routed between the upper and lower chords. Duct openings Dare defined by a pair of spaced-apart vertical inner web members VW, oneon each side of the midpoint of the truss, and by the upper and lowerchords. It will be understood, however, that apparatus of this inventionmay also be utilized to fabricate trusses of other configurationswithout the abovesaid duct openings, and with suitable modification tofabricate other types of wood structures, such as wall sections havingupper and lower plate members with wall studs extending perpendicularlytherebetween and secured thereto by nailing plates with the upper andlower plates corresponding generally to the upper and lower chords UCand LC and with the studs corresponding generally to the webs W of trussT. Apparatus 1 comprises a pair of presses, as indicated at 30, 3b, eachhaving an upper platen 5 and a lower platen 7 (see FIGS. 5 and 10) whichare relatively movable toward and away from one another for drivingnailing plates N into two or more of the wood members from above andbelow (see FIG. 8) thereby to rigidly secure the wood members togetherat the joints of the truss. The apparatus further includes means, asindicated generally at 9, including a plurality of lumber platforms orsupports 11 and arms 13 cantilevered from each support for holding thewood members in position so that they may properly be joined together bynailing plates N, the support and the cantilever arms togetherconstituting cantilever means. In FIGS. 2 and 5, it can be seen that thecantilevered arms 13 support the wood members with clearance for thepress below the arms. Each of the presses is mounted on a respectivepress carriage 15a,

15b movable lengthwise of apparatus 1 along a respective track 17a, 17badjacent the upper and lower chords, respectively, of a truss fordriving nailing plates at each joint along the respective chord of thetruss. Each press, as it is carried by its carriage, moves along itstrack in a generally lateral direction with respect to the press into anoperating position (see FIG. 8) at a first support 11 for drivingnailing plates into the wood members, and after driving the nailingplates moves generally sidewise out of its operating position at thefirst support and into its operating position at a next successivesupport along its respective chord. Each press 3a, 3b and its respectivepress carriage 15a, 15b are movable along their respective tracksindependently of one another to automatically drive nailing plates ateach support along their respective chord. Movement of the presses iscontrolled by means, generally indicated at 19. Briefly, thiscontrolling means in cludes means 21 (see FIG. 10) movable with eachcarriage and press for sensing the approach of the press to itsoperating position at a support from one direction or the other alongthe chord of the truss in advance of its arrival at its operation toinitiate deceleration of the carriage and for sensing the arrival of thepress at its operating position at a support so as to stop movement ofthe press at its operating position and to initiate operation of thepress for driving nailing plates into the wood members. After drivingnailing plates into the wood members at the first support, the press isautomatically moved sidewise out of the first support to its operatingposition at the next successive support along its respective chord. Thisis repeated until all the nailing plates have been driven into the woodmembers along this respective chord.

More particularly, holding means 9 includes a pair of frames 23(constituting a central support means) arranged end-to-end along a linewith each of the frames carrying a series of supports 11 (constituting aseries of support means) for holding upper and lower chord members andweb members in position for being secured together by nailing plates Nto 'form a truss. The inner ends of the frames 23 are spaced apart asufficient distance (e.g., about 9-10 feet) to allow workmen to walkbetween the inner end of each frame and the press carriages 15a, 15bwhen the latter are positioned substantially midway between the framesin a parking position (see FIG. 1). This facilitates the removal of acompleted truss from the apparatus. With the frames 23 so arranged,workmen may be positioning wood members on one of the frames whilepresses 3a, 3b move along the chords of the truss being formed in theother of the frames thereby facilitating rapid production of trusseswith a minimum of labor. As shown in FIG. 4, each frame 23 includes aseries of posts 25 arranged in a row secured to and extending up fromthe floor and a horizontal member 27 carried by the upper ends of theposts and extending the length of the frame.

As is shown in FIG. 5, the series of posts 25 and the horizontal member27 are generally coplanar and they permit the press carriages l5a,l5b'to pass in close proximity to the center plane of the frame as thepress carriages move along the chords of the truss being formed and thuspermit shallow-depth trusses to be fabricated. A pair of clampingchannels 29 is secured, as by welding, to the upper face of thehorizontal member and extends longitudinally thereof for slidablyreceiving portions of two series or rows of supports 11, one on eachside of the center plane of frame 23, for a respective chord of thetruss to be fabricated, the supports being movable independently of oneanother along the length of the frame for being positioned at the jointsof a truss to be formed. Also, with this arrangement, the supports arepositioned in close back-to-back spaced relation with the cantileverarms 13 extending laterally outwardly of the frame 23. Thus, thesupports may be arranged to fabricate trusses of relatively shallowdepth.

In FIG. 5, each support (or cantilever means) 11 is shown to comprise avertical back plate 31 having outwardly facing flange 33 at its lowerend engageable with a respective clamping channel 29. Each flange 33carries means, as indicated at 34, for releasably clamping the supportto its respective clamping channel at any position therealong. Arms 13are cantilevered from the upper margin of the plate in side-by-sidespaced relation (see FIG. 8) for supporting wood members on the topsurfaces of the arms in position for being secured together by nailingplates N at a location between the arms. As is best shown in FIG. 5,each support is adapted for lateral entry of the lower platen 7 of arespective press 3a, 3b from one side or the other of the support belowthe cantilevered arms 13 to its operating position between the arms withthe planes of 5 the tops of the arms co-planar and with these planesspaced from the top surface of the lower platen 7 a distance sufficientto accommodate a nailing plate arranged with its teeth pointing upwardlyfor being driven into the wood members from below (see FIG. 8). Thecantilever arms 13 are laterally spaced from one another a distancegreater than the width of the lower platen of the press for entry of thelower platen of the press between the arms when the lower platen ismoved upwardly to drive a nailing plate N upwardly into the wood memberssupported on the arms. Each cantilever arm 13 has a pair of inwardlyprojecting lugs 35 (see FIG. 8) secured thereto adjacent its lower edgesfor supporting a holder plate 37. These lugs support the holder plate 37in a manner which permits it to be freely moved upwardly by the lowerplaten 7 of the press as the lower platen moves upwardly to drive anailing plate N resting on the holder plate into the wood members frombelow. With the holder plate resting on the lugs, it is spaced from thewoood members a distance sufficient to accommodate a nailing plate N.

The operating position of a press 3a, 3b at one of the supports 11 ismore particularly defined as that position in which the press and itsplatens are substantially centered with respect to the cantilever arms13 and the platens are positioned vertically relative to the woodmembers and fore and aft relative to plate 31 of the support so as to beabove and below the joint in the wood members with the lower platen 13below holder plate 37 when the latter is in its lowered positionsupported by lugs 35 and with the upper platen 5 above the joint in thewood members. Thus, with the press in its operating position, the pressmay be operated to drive nailing plates into the wood members withoutdamage to the supports. The operating position of the press is mostclearly illustrated in FIGS. 5 and 8.

A stop 39 engageable with the outer face of a respective chord member UCor LC is slidably received by each cantilever arm 13, each stop beingmovable to any position along the length of its respective arm and beingreleasably secured to its arm by means of a clamping bolt 41. Stops 39are positioned on the arms in predetermined positions relative to thecenter plane of frame 23, with the stops for the lower chord memberbeing spaced from the stops for the upper chord members a distancecorresponding to the depth of the truss thereby to prevent outwardmovement of the chord members during fabrication of the truss. It willbe understood that the stops 39 may be positioned to slightly bow theupper and lower chords so that the fabricated truss has a slight bow tocompensate for any sag due to the weight of the truss when the truss isplaced in the building. Power operated means, indicated at 43 in FIG. 9,is provided for securely holding the upper chord members UC, the lowerchord members LC and the web members W in position on supports 11 forbeing secured together by nailing plates N. Power operated means 43comprises a pair of opposed air cylinder units 45 each having a ram 47movable outwardly to ward the ends of the truss. These air cylinderunits are secured to a mounting plate 49 which is adapted to bereleasably secured to arms 13 of one or more supports 11 so that the aircylinder units are substantially centered with the duct opening D0 ofthe truss to be formed. Each ram $7 is engageable with the inner face ofan adjacent vertical web VW, preferably adjacent the end thereof incontact with the end of an adjacent angled web W. An adjustable stop 51is carried by an arm 13 of an adjacent support 11 so as to hold thevertical webs VW in position upon actuation of the air cylinder units45. To initiate clamping of the wood members, a manually operatedpush-type valve 53 is provided between the air cylinders. Air issupplied to valve 53 by means of an air distribution system 54 includedwith frame 23 at the center portion thereof. This air distributionsystem permits the position of the supports 11 readily to be adjustedalong clamping channels 29. Upon operation of the valve 53, rams 47extend to engage the inner faces of their respective vertical webs VW.As each vertical web engages stop 51, continued actuation of the ramcauses the other end of the vertical web to push against the adjacentangled web, thus forcing this web into engagement with the inner facesof both the upper and lower chords, and forcing the chords into firmengagement with stops 39, and further forcing the other web members intocontact with the inner faces of the chords all along the truss. Thisclamping force is maintained until all the joints of the truss have beensecured by nailing plates N. Each of the air cylinder units 45 is aspring return cylinder for automatically retracting its ram upon ventingof air pressure from the cylinder. As is shown in FIGS. 2, 3 and 6, anabutment frame 55 releasably secured to the arms 13 of the outersupports 11 at each end of the truss being formed for preventing endwisemovement of the outermost web member relative to the chord membersbeyond a desired position. The abutment frame 55 is shown in thedrawings to be engaged by a vertical end web, but it will be understoodthat other abutment frames may be used when the outermost web member ofthe truss is angled rather than vertical. It will also be understoodthat the arrangement of clamping air cylinders 45 may be adapted for usewith trusses having angled innermost web members rather than verticalwebs VW. It will be further understood that the poweroperated means 43may also be constituted by a toggle or scissors linkage actuated by anair cylinder to apply clamping forces to the vertical webs so as toforce them endwise of the truss.

As is shown in FIG. 6, means, as indicated at 57, is provided forlifting or ejecting a completed truss T clear of supports 11, stops 39and. abutment frames 55 so as to facilitate removal of the completedtruss from the apparatus. More particularly, lifting means 57 comprisesa plurality of lifting or ejector units, each indicated at 59 and eachincluding a mounting bracket 61 releasably secured to frame 23, a liftcylinder unit 63 pivotally carried by the bracket for swinging between astowed position (see FIGS. 2 and 5) in which the lift cylinder is inline with posts 25 (i.e., substantially within the longitudinalcenterplane of holding means 9) so that press carriages 15a, 15b maymove past the lift units and a lifting position (see FIG. 6) in whichthe lift cylinder is swung out from the line of posts 25 and in whichits piston rod 65 is movable from a lowered retracted position to araised lifting position so that an arm 67 carried on the upper end ofthe lift cylinder piston rod is engageable with one or more of the woodmembers of the completed truss for lifting it clear of the supports 11and stops 39. Arm 65 carries a series of rollers 69 engageable withvarious wood members of the completed truss enabling the truss to berolled from apparatus after it has been lifted clear of the supports.Lift units 59 also include a swing cylinder unit 71 interconnectedbetween the mounting bracket 61 and lift cylinder 63 for effectingswinging of the lift cylinder between its stowed and lifting positions.

As is shown in FIG. 5, horizontal member 27 has a pair of guide channels73 secured to its bottom, these channels extending between posts 25.Each mounting bracket 61 has a plurality of clamping lugs 75 at itsupper end which are received by the guide channels. Thus, each liftingunit 59 is movable along the horizontal member to any desired positionat which its arm 63 may most advantageously engage the wood members forenabling rolling of the truss. Operation of lifting means 57 is effectedautomatically upon the completion of the truss after the presses 3a, 3bhave moved clear of the truss and after clamping cylinders 45 have beenreleased. Means (not shown) are provided in the air supply system forthe lift units which prevents movement of the lift cylinder 61 of eachlift unit from its lowered retracted position to its raised liftingposition until after its swing cylinder 67 has swung the lift cylinderfrom its stowed to its lifting position.

Presses 3a and 3b and press carriages a, 15b are essentially identicaland for that reason only one press 3b and its respective press carriage15b need be described in detail. As is shown in FIG. 2, each track means17a, 17b for the press carriages includes an inverted V- shaped rail77'adjacent frames 23 and a flat outer rail 79, these rails extendingthe length of apparatus 1 from one frame 23 to the other. Press carriage15b comprises a base 81 mounted on a pair of grooved rollers 83 rollingon the inverted V-rail for guiding the carriage along the track, and ona pair of rubber-tire drive wheels 85 engageable with the flat rail 79for driving the carriage along the track. As is shown in FIG. 5, drivewheels 85 are driven by a reversible hydraulic motor 87, this motor alsoconstituting means for decelerating and stopping the carriage. Base 81has an electrically driven hydraulic pressure unit generally indicatedat 89 mounted thereon including an electric motor M-l, a hydraulic pumpand a hydraulic fluid reservoir (see FIG. 10). This hydraulic unitsupplies hydraulic fluid under pressure to motor 87 for driving thecarriage along the track and for operating press 3b. Power for theelectric motor is supplied by means of a respective bus 97 carried bythe frames 23. Press 3b includes a C- shaped press frame 97 and a fluidpower cylinder 99 operable for effecting movement of the upper platen 5and the lower platen 7 toward and away from one another. The press alsoincludes means (not shown) for preventing the platens of the press fromexerting unequal forces on the arms 13 as the nailing plates N aredriven into the wood members, so as to prevent damage to the arms. Thislast-said means may be of the type shown in the co-assigned U.S. patentapplication Ser. No. 696,323 now U.S. Patent No. 3,728,958 or othersimilar means known in the art. The press carriage has a pair of spacedsupports 101 extending up from base 81 for mounting the press inposition for driving nailing plates into the wood members. The press ismounted c. rollers 103 (see FIG. 5) received in a respective track 104secured to the upper, inner portions of supports 101 in a manner similarto the way in which the presses in the above-mentioned co-assignedapplication are mounted in their respective stands, thus enabling thepress to be moved in and out relative to frame 23 and thus allowing thetop platen 5 to be moved clear of its respective truss chord. Also,rollers 103 permit the press to be moved in and out to fabricate trussesof various depths. At each end of the carriage, a pivoted safety bar 105is provided for actuating a respective safety switch LS-ll or LS-l3.Upon movement of either safety bar from the position shown in FIG. 2, asmay be occasioned by the safety bar striking a person on tracks 17a, 17bas the carriage moves therealong, the carriage is brought to animmediate halt. As a further safety measure, each carriage has aflashing beacon 106 and a warning horn (not shown) operable when thecarriage is in operation.

The previously mentioned sensing means 21 for each carriage 15a, 15bfurther includes means 107 for selectively effecting operation of thesensing means so as to sense the approach of its respective press 3a, 3bto its operating position at each support 11 from one direction or theother along a chord of the truss being fabricated. Again, carriage 15aand press 3b will be referred to in describing means 21 and 107, but itwill be understood that the means 21 and 107 of carriage 15a and press3a are essentially identical. Briefly, this sensing means comprises twopairs of switches LS-7L and LS- 8R, LS-7R and LS-8L (see FIGS. 10, 11and 12) carried by the press carriage adjacent the lower platen 7 of itsrespective press. Switches LS-7L and LS-8R are operable as the press 3bmoves from right to left (as viewed in FIG. 2) and switches LS-7R andLS-8L are operable as the press moves from left to right. One switch ofeach pair is actuated by means, as indicated at 109 in FIG. 5, carriedby each support 11 as the press approaches its operating position at asupport for initiating deceleration of the press carriage 15b and theother of the switches is actuable by the actuating means 109 forstopping movement of the press carriage along the track 17b with thepress in its operating position at one of the supports 11. With both ofthe switches actuated, circuits, as will appear, are energized toinitiate closing of the press to drive nailing plates N into the woodmembers. Preferably, switches LS-7L, LS-8R, LS-7R and LS-8L are magneticproximity switches of the type actuable in response to a magnetic fieldof a predetermined strength, and the actuating means 109 comprises apair of magnets 111a, lllb (see FIG. 8) secured to plate 31 at each ofthe supports. As is shown in FIG. 5, magnets 111a, lllb and the magneticswitches are positioned on the support and on the press carriage so thatthe switches pass in close proximity to the magnets as the presscarriage moves along the track thereby to actuate the switches as theypass by the magnets. As is shown in FIG. 10, the switches of each pairare spaced apart a predetermined distance (about 18-20 inches) and themagnets 111a, lllb on each of the supports are spaced a correspondingdistance so that when the press is in its operating position, bothswitches of each pair are actuated by the magnets. Although magneticswitches are shown, it will be understood that mechanically operatedlimit switches or other proximity sensing means (e.g., photoelectriccells) may also be used.

Referring to the block diagram of the sensing means 21 shown in FIG. 11,operation of the sensing means may more fully be explained. Startingwith both press carriages a, 15b in their parked positions between theadjacent ends of frames 23 and with the wood members clamped to thesupports 11 of the left frame (as viewed in FIG. 1), operation of eachof the press carriages is initiated by operating a lever or joystick"113 (see FIG. 2). As can be seen in FIGS. 12 and 13, movement of thecarriage to the right or left is controlled by lever 113 and this leverthus constitutes means 107 for effecting operation of sensing means 21so as to sense the approach of the press to its operating position fromeither direction along the chord of the truss to be fabricated.Operation of lever 113 initiates an automatic carriage cycle whichcauses each of the press carriages to accelerate from its parkedposition toward the first support 11 of the left frame 23. Again, onlymovement of carriage 15b need be described as movement of carriage 15ais essentially identical. As the lower platen 7 of the press moves underthe arms 13 of the first support 1], switch LS-7L is energized by themagnet lllb on the right side of the first support to decelerate, butnot stop, the press carriage by reducing the flow of hydraulic fluid tohydraulic motor 87, and thus exerting a braking force on the carriage.The carriage continues to move slowly to the left until the rightmostswitch, LS-8R, is actuated by the magnet lllb thereby to brake thecarriage to a halt with its press 3a, 3b properly docked or positionedat its operation between arms 13. With the press so positioned, switchLS-7L is actuated by the left magnet 111a, and the switch LS-SR isactuated by the right magnet lllb. With both switches actuated, theoperating position of the press is verified and operation of the pressis initiated to automatically drive nailing plates N into the woodmembers at the first support. After the maximum hydraulic pressure hasbeen applied to fluid cylinder 99 of the press, thereby indicating thenailing plates have been driven fully into the wood members, the pressis automatically opened. As the platens are moved to their fully openpositions, a switch LS-lO is tripped to initiate the next automaticpress carriage cycle. The automatic press carriage cycle are automaticpress cycle are repeated until the press carriage has moved succesivelyfrom the first support to the last or outermost support along the leftframe 23. As each carriage approaches the last support 11, a magneticswitch LS-2 (referred to as a reverse switch) carried by the carriage isactuated by a magnet (not shown) on the last support. After theautomatic press cycle at the last support, the reverse switch causes thepress to return to its parked position. Upon approaching its parkedposition, a switch LS-S is energized causing the carriage to decelerate.The carriage continues to travel to the right until it reaches itsparked position, when a park position switch LS-16 is actuated. Thisswitch LS-16 stops the carriage in its parked position. When bothcarriages 15a, 15b have returned to their parked positions and theirrespective switches LS-16 are tripped, release of wood clampingcylinders 45 and operation of the lift units 59 are initiated to liftthe completed truss clear of the supports 11 and stops 39 to facilitateremoval of the truss. The press carriage is then ready for re-cycling.

The operation of the press carriage control means 19 15b will beapparent to one skilled in the art. In FIGS. 12 and 13, 8-1, 8-2, 5-3etc. indicate manually actuated swtiches, LS-2, LS-S, LS-7 etc. indicateautomatically actuated switches, relay coils are: indicated as CR-l,CR-Z, CR-3, etc. with the relay contacts indicated as CR-lD, CR-2D etc.,time delay relays are indicated at TR-S, TR-6 etc. with time delay relaycontacts indicated as TR6A, TR-SD etc., and pressure actuated switchesare indicated at PS1 and PS-2.

It will be noted if the press carriages 15a, 15b are moved slowly alongtheir respective tracks 17a, 17b, it may be possible to stop movement ofthe carriage with their respective press 3a,3b properly positioned atits operating position at a support 11 without first sensing theapproach of the press to its operating position and initiatingdeceleration of the carriage. It will also be noted that means otherthan hydraulic motor 87 may be used to drive the carriage along thetrack. For example, a chain (not shown) may be attached to the carriage,the chain extending along the length of the track from both sides of thecarriage and being movable by a power driven sprocket remote from thecarriage operable to effect movement of the press from its operatingposition at one stand to another, with controlling means 19 beingoperable to control the above-said sprocket thereby to effect movementof the press carriage along its track from its operating position in onesupport to its operating position at each successive support.

In view of the above, it will be :seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. Apparatus for fabricating wood structures, such as trusses of thetype having lower chord members, upper chord members and web membersextending from the lower chord members to the upper chord members, saidapparatus comprising two presses each having an upper and a lower platenwhich are relatively movable toward and away from one another fordriving nailing plates into two or more of the wood members of a trussfrom above and below, means for supporting the wood members which are tobe joined together by said nailing plates, said supporting meansincluding a plurality of supports and means cantilevered relative toeach support for holding wood members with clearance therebelow, meansmounting one of the presses adjacent said upper chord and means mountingthe other press adjacent said lower chord for movement of each pressalong its respective chord into an operating position at a first supportfor driving nailing plates into the wood members, and for movement in agenerally lateral direction with respect to the press sidewise out ofits operating position at said first support and into its ating positionthereby to initiate deceleration of said.

mounting means and for sensing the arrival of the press at its operatingposition at the last-said support so as to stop movement of the press atitsoperating position for driving nailing plates into the wood members.

2. Apparatus as set forth in claim 1 wherein said sensing means furtherincludes means for sensing the approach of the press to its operatingposition at each support from one direction along its respective chordand for sensing registration of the press at its operating position ateach support, and means for effecting operation of said sensing means soas to sense the approach of said press to its operating position at eachsupport from the other direction along its respective chord.

3. Apparatus as set forth in claim 2 wherein said sensing means furthercomprises actuating means at each support and switch means carried alongwith the press, said switch means being actuable by said actuating meansas the press approaches its operating position at a support forinitiating deceleration of the press mounting means and being furtheractuable by the actuating means for stopping movement of the pressmounting means with the press in its operating position at one of saidsupports.

.4. Apparatus as set forth in claim 3 wherein said switch meanscomprises a first proximity switch carried along with the press actuableby said actuating means as the press approaches its operating positionat a support for initiating deceleration of the press mounting means anda second proximity switch carried along with the press actuable by saidactuating means for stopping the press mounting means when the press isin its operating position at a support.

5. Apparatus as set forth in claim 4 wherein said first and secondproximity switches are magnetic switches actuable in response to amagnetic field of a predetermined strength, and wherein said actuatingmeans at each support comprises at least one magnet of sufficientstrength to actuate said first and second proximity switches as theymove past the magnet, said magne. being positioned on the support andsaid proximity switches being positioned on the carriage so that saidproximity switches pass in close spaced relation to the magnet as thepress approaches and moves into its operating position.

6. Apparatus as set forth in claim 5 wherein said actuating meanscomprises a pair of said magnets, said proximity switches being spacedapart a predetermined distance and said magnets being spaced on thesupport a distance corresponding to the spacing of the proximityswitches so that with the press in its operating position both of saidswitches are actuated by said magnets so as to stop the press in itsoperating position and so as to initiate operation of the press fordriving nailing plates into the wood members.

7. Apparatus as set forth in claim 2 wherein said supporting meanscomprises a first frame and a second frame, each frame carrying a seriesof supports for holding said upper chord members, lower chord membersand web members in position for being secured together by nailing platesso as to fabricate a truss on the supports of each of the frames, saidframes being arranged in end-to-end relation relative to one another :2that said presses carried by said press mounting means may move alongthe chords of respective trusses to be formed on each frame for drivingnailing plates into the wood members at the joints of the trusses to befabricated.

8. Apparatus as set forth in claim 7 wherein the supports for the upperchord members and the supports for the lower chord members on each saidframe and arranged in close back-to-back spaced relation and are movablerelative to one another longitudinally along their respective frame.

9. Apparatus as set forth in claim 8 wherein each support comprises avertically disposed plate extending up from said frame, and wherein saidcantilevered means comprises two cantilevered arms in side-by-sidespaced relation adapted to support wood members in position for beingsecured together by the nailing plates at a location between the arms,said support being adapted for lateral entry of the lower platen of oneof the presses from one side or the other thereof below saidcantilevered arms to its operating position between said arms with theplaneof the top surfaces of the arms spaced from the top surface of thelower platen a distance sufficient to accommodate a nailing platearranged with its teeth pointing upwardly for being driven into the woodmembers from below, the cantilever arms being laterally spaced from oneanother a distance greater than the width of the lower platen of thepress for entry of the lower platen of the press between the arms whenthe lower platen is moved upwardly to drive the nailing plate upwardlyinto the wood members.

10. Apparatus as set forth in claim 8 further comprising track means oneach side of said frames extending from the outer end of the first frameto the outer end of the second frame, each said press mounting meanscomprising a power driven carriage movable in one direction along itsrespective track means for moving its respective press to its operatingposition at one of the supports carried by said first frame into itsoperating positions at each successive support along its respectivechord of the first frame and movable in the other direction along itsrespective track means for moving its press to its operating position atone of the supports carried by the second frame and to its operatingpositions at each successive support along its respective chord of saidsecond frame.

11. Apparatus as set forth in claim 10 wherein said first and secondframes are arranged in a line and are spaced apart from one another,wherein each of said press carriages is initially positioned at aparking position between the frames and wherein, upon the initiation ofmovement of said carriage in said one direction along its respectivetrack means, said press is automatically moved in said one directionalong its track means from its parking position to its operatingposition at a first support adjacent the inner end of said first framefor driving the nailing plates into the wood members at said firstsupport of said first frame and then is automatically movable to itsoperating position at each successive support along its respective chordof said first frame until all joints along its respective chord havebeen secured together, said press carriage then being automaticallymovable to its parking position, and upon initiation of movement of thepress carriage in said other direction along its respective track means,said press is automatically moved from its parking position to itsoperating position at a first support adjacent the inner end of saidsecond frame for driving nailing plates into the wood members at saidfirst support of said second frame and is automatically moved to itsoperating position at each successive support along its respective chordof said second frame until all joints along its respective chord havebeen secured together, said press carriage then being automaticallymovable to its parking position.

12. Apparatus as set forth in claim 1 wherein said supporting meansfurther comprises a frame for carrying a plurality of said supports withthe supports for the upper chord members and the supports for the lowerchord members being in close back-to-back spaced relation and beingmovable relative to one another longitudinally along said frame.

13. Apparatus as set forth in claim 12 wherein each support includesmeans for securing it to said frame at any position therealong.

14. Apparatus as set forth in claim 13 wherein each support comprises avertically disposed plate extending up from said frame, and wherein saidcantilevered means comprises two cantilevered arms in side-by-sidespaced relation adapted to support wood members in position for beingsecured together by the nailing plates at a location between the arms,said support being adapted for lateral entry of the lower platen of apress from one side or the other thereof below said cantilevered arms toits operating position between said arms with the plane of the topsurfaces of the arms spaced from the top surface of the lower platen adistance sufficient to accommodate a nailing plate arranged with itsteeth pointing upwardly for being driven into the wood members frombelow, the cantilever arms being laterally spaced from one another adistance greater than the width of the lower platen of the press forentry of the lower platen of the press between the arms when the lowerplaten is moved upwardly to drive a nailing plate upwardly into the woodmembers.

15. Apparatus as set forth in claim 14 further comprising track means oneach side of said frame parallel to said upper and lower chords of thetruss to be fabricated, and wherein each said press mounting meanscomprises a power driven carriage movable along a respective track meansfor moving its press from its operating position at one of said supportsto its operating position at each successive support along itsrespective chord.

16. Apparatus as set forth in claim 1, further comprising means forlifting a completed truss clear of said support, said lifting meansbeing swingable from a stowed position in which it permits movement ofsaid press mounting means therepast, and a lifting position in which itis engageable with one or more wood members of a fabricated truss forlifting the completed truss clear of the supports.

17. Apparatus as set forth in claim 16 wherein said lifting meansincludes a plurality of rollers engageable with the completed truss toenable rolling of the completed truss from the apparatus when it islifted clear of the supports.

18. Apparatus as set forth in claim 17 wherein said lifting meanscomprises a plurality of lifting units each comprising a mountingbracket adapted to be secured to said main frame, a lift cylinder unitpivotally carried by said bracket for swinging between said stowedposition and said lifting position, and a swing cylinder un t foreffecting swinging of the lift cylinder unit between its stowed andlifting positions, said lift cylinder having an arm engageable withmembers of the completed truss, said arm being movable between a loweredretracted position and a raised position in which it is engageable withthe completed truss for lifting it clear of the supports.

19. Apparatus as set forth in claim 18 wherein said lifting meansincludes means for preventing movement of the lift cylinder unit fromits lowered retracted position to its raised position until said swingcylinder unit has fully swung the lift cylinder unit from its stowed toits lifting position.

20. Apparatus as set forth in claim 18 wherein said arm has a pluralityof rollers engageable with various wood members of said completed trussenabling rolling of the completed truss from the apparatus after it hasbeen lifted clear of the supports.

21. Apparatus as set forth in claim 1 wherein the truss to be fabricatedis a flat truss with its upper and lower chords substantially parallelto one another, with the innermost web members of the trusssubstantially perpendicular to the chords, and with others of the websangled with respect'to the chords and having their ends in contact withthe ends of adjacent webs and with the inner faces of said chordmembers, said apparatus further comprising means for clamping said chordmembers and web members in position so as to be rigidly secured togetherby nailing plates, said clamping means comprising a plurality of stopscarried by said cantilever means engageable by the outer faces of thechord members thereby to hold the chord members in desired spacedrelation, and power operated means engageable with the opposed innerfaces of said vertical webs for applying a force thereagainst so as toforce all the web members into abutting relation with one another andwith the inner faces of the chord members from one end of the truss tothe other and to hold the chord members in abutting relation with saidstops, and means at each end of the truss for preventing endwisemovement of the outermost web member relative to the chord membersbeyond a desired position.

22. Apparatus for fabricating flat wood trusses of the type having lowerchord members, upper chord members and web members extending from thelower chord members to the upper chord members, with said upper andlower chord members substantially parallel to one another, with theinnermost web members substantially perpendicular to the chord membersand with the other of the webs angled with respect to the chords andhaving their ends in contact with the ends of adjacent web members andwith the inner faces of said chord members, said apparatus comprisingmeans for driving nailing plates into two or more of the wood members ofa truss, means for holding the wood members in position for being joinedtogether by said nailing plates including a series of supports, andmeans for clamping said chord members and web members in position so asto be rigidly secured together by nailing plates, said clamping meanscomprising a series of stops carried by said supports engageable by theouter faces of said chord members thereby to hold the chord members indesired spaced relation, and power operated means engageable with thefaces of each of said perpendicular webs facing one another for applyinga force thereagainst so as to force all the web members into abuttingrelation with one another and with the inner faces of the chord membersfrom one end of the truss to the other and to hold the chord members inabutting rela tion with said stops, and means at each end of the trussfor preventing endwise movement of the outermost web member relative tothe chord members beyond a desired position.

23. Apparatus for fabricating wood structures, such as trusses of thetype having lower chords, upper chords and web members extending betweenthe chords, said apparatus utilizing at least one press having an upperplaten and a lower platen which are relatively movable toward oneanother for driving nailing plates into two or more of the wood membersat the joints of said truss thereby to rigidly secure the wood memberstogether, said apparatus comprising means for holding said wood membersin position for being secured together by said nailing plates, meansmounting the press for movement along one chord of the truss to befabricated in close proximity to the holding means for driving nailingplates into the wood member at each joint along said one chord of thetruss, and lifting means carried by said holding means swingable betweena stowed position substantially in the longitudinal vertical centerplaneof said holding means in which said press mounting means and said pressmay move therepast and a lifting position substantially perpendicular tosaid centerplane and in the path of said press as the latter moves alongsaid one chord in which said lifting means is engageable with one ormore of the wood members of the completed truss for lifting thecompleted truss clear of said holding means.

24. Apparatus for fabricating wood structures, such as trusses of thetype having lower chords, upper chords and web members extending betweenthe chords, said apparatus utilizing at least one press having an upperplaten and a lower platen which are relatively movable toward oneanother for driving nailing plates into two or more of the wood membersat the joints of said truss thereby to rigidly secure the wood memberstogether, said apparatus comprising means constituting supports forholding said wood members in position for being secured together by saidnailing plates, means mounting the press for movement along one chord ofthe truss to be fabricated in close proximity to the holding means fordriving nailing plates into the wood member at each joint along said onechord of the truss, and lifting means carried by said holding meansswingable between a stowed position in which said press mounting meansmay move therepast and a lifting position in which it is engageable withone or more of the wood members of the completed truss for lifting thecompleted truss clear of said supports, said lifting means furthercomprising a plurality of lifting units each having a mounting bracketadapted to be secured to said frame, a lift cylinder unit pivotallycarried by said bracket for swinging between said stowed position andsaid lifting position, and a swing cylinder unit for effecting swingingof the lift cylinder unit between its stowed and lifting positions, saidlift cylinder unit having an arm engageable with members of thecompleted truss, said arm being movable between a lowered retractedposition and a raised position in which it is engageable with thecompleted truss for lifting it clear of the supports.

Apparatus as set forth in claim 24 wherein said lifting means includesmeans for preventing movement of the lift cylinder unit from its loweredretracted pottion to its raised position until said swing cylinder unithas fully swung the lift cylinder unit from its stowed to its liftingposition.

26. Apparatus as set forth in claim 25 wherein said arm has a pluralityof rollers engageable with various wood members of said completed trussenabling rolling of the completed truss from the apparatus after it hasbeen lifted clear of the supports.

27. Apparatus for fabricating wood structures, such as trusses of thetype having lower chord members, upper chord members and web membersextending from the lower chord members to the upper chord members, saidapparatus comprising a press having an upper and a lower platen whichare relatively movable toward and away from one another for drivingnailing plates into two or more of the wood members of a truss fromabove and below, means for supporting the wood members which are to bejoined together by said nailing plates, said supporting means includinga plurality of supports and means cantilevered relative to each supportfor holding wood members with clearance therebelow, means mounting thepress adjacent one of said chords for movement of the press from onedirection or the other along its respective chord into an operatingposition at a first support for driving nailing plates into the woodmembers, and for movement in a generally lateral direction with respectto the press sidewise out of its operating position at said firstsupport and into its operating position at a next successive supportalong its respective chord, means for controlling movement of the pressmounting means including means movable therewith for sensing theapproach of said press from one direction along its respective chord toits operating position at a support in advance of its arrival at itsoperating position thereby to initiate deceleration of said mountingmeans and for sensing the arrival of the press at its operating positionat the lastsaid support so as to stop movement of the press as itsoperating position for driving nailing plates into the wood members, andmeans for effecting reversal of said sensing means to sense the approachof said press from the other direction along its respective chord to itsoperating position at a support in advance of its arrival at itsoperating position at the last-said support thereby to initiatedeceleration of said mounting means and for sensing the arrival of thepress at its operating position at the last-said support so as to stopmovement of the press at its operating position for driving nailingplates into the wood members.

28. Apparatus for fabricating wood structures, such as trusses of thetype having lower chord members, upper chord members and web membersextending from the lower chord members to the upper chord members, saidapparatus comprising two presses each having an upper and a lower platenwhich are relatively movable toward and away from one another fordriving nailing plates into two or more of the wood members of a trussfrom above and below, a first and second series of support means forsupporting the wood members which are to be joined together by saidnailing plates, each series including central supporting means andcantilevered means extending laterally outwardly therefrom on oppositesides thereof, said cantilever means being arranged in two rows, one oneach lateral side of the central supporting means for holding memberswith clearance for the lower platens of the presses therebelow, saidfirst and second series being arranged in a line in end-to-end relationrelative to one another, means mounting each of the presses, one presson one side of said line and the other press on the other side of saidline, for movement of the presses independently of one another alongsaid rows, for movement of each press into an operating position at arespective cantilever means so as to drive nailing plates into themembers, and for movement in a generally lateral direction with respectto the press sidewise out of its operating position at said cantilevermeans and into its operating position at a next successive cantilevermeans, said series being spaced apart from one another so that with saidpress mounting means positioned between the first and second series in aparking position, a workman may walk between the ends of either seriesand the press mounting means.

29. Apparatus as set forth in claim 28 further comprising means forcontrolling movement of each press mounting means along its respectivesaid row, operable to stop the press at its operating position at eachof said cantilever means for driving nailing plates into the members.

30. Apparatus as set forth in claim 29 wherein said cantilever means arearranged in close back-to-back spaced relation and are movable relativeto one another longitudinally along said line to different positions.

31. Apparatus as set forth in claim 29 wherein each cantilever meanscomprises a vertically disposed plate extending up from said frame, andtwo cantilevered arms in side-by-side spaced relation adapted to supportwood members in position for being secured together by the nailingplates at a location between the arms, said cantilever means beingadapted for lateral entry of the lower platen of one of the presses fromone side or the other thereof below said cantilevered arms to itsoperating position between said arms with the plane of the top surfacesof the arms spaced from the top surface of the lower platen a distancesufficient to accommodate a nailing plate arranged with its teethpointing upwardly for being driven into the wood members from below, thecantilever arms being laterally spaced from one another a distancegreater than the width of the lower platen of the press for entry of thelower plater of the press between the arms when the lower platen ismoved upwardly to drive the nailing plate upwardly into the woodmembers.

32. Apparatus as set forth in claim 29 further comprising track means oneach side of said line extending from the outer end of the first seriesto the outer end of the second series, each said press mounting meanscomprising a power driven carriage movable in one direction along itsrespective track means for moving its respective press to its operatingposition at each successive cantilever meansalong each of said series.

33. Apparatus as set forth in claim 32 wherein, with said presscarriages initially positioned in their parking positions between saidseries and wherein upon the initiation of movement of one of saidcarriages in said one direction along its respective track means, thepress of said one carriage is automatically moved in said one directionalong its track means from its parking position to its operationposition at a cantilever means adjacent the inner end of said firstseries for driving nailing plates into the wood members at said firstcantilever means and then is automatically movable to its operatingposition at each successive cantilever means along said first seriesuntil all joints therealong have been secured together, said presscarriage then being automatically movable to its parking position, andupon initiation of movement of the press carriage in said otherdirection along its respective track means, said press is automaticallymoved from its parking position to its operating position at a firstcantilever means adjacent the inner end of said second series fordriving nailing plates into the wood members at said first cantilevermeans of said second series and is automatically movable to itsoperating position at each successive cantilever means along said secondseries until all joints therealong have been secured together, saidpress carriage then being automatically movable to its parking position.

34. Apparatus as set forth in claim 28 further comprising means forlifting a completed truss from said supporting means of each of saidframes, and means for preventing operation of said lifting means whenoneof said press mounting means is moved from its parking position.

1. Apparatus for fabricating wood structures, such as trusses of thetype having lower chord members, upper chord members and web membersextending from the lower chord members to the upper chord members, saidapparatus comprising two presses each having an upper and a lower platenwhich are relatively movable toward and away from one another fordriving nailing plates into two or more of the wood members of a trussfrom above and below, means for supporting the wood members which are tobe joined together by said nailing plates, said supporting meansincluding a plurality of supports and means cantilevered relative toeach support for holding wood members with clearance therebelow, meansmounting one of the presses adjacent said upper chord and means mountingthe other press adjacent said lower chord for movement of each pressalong its respective chord into an operating position at a first supportfor driving nailing plates into the wood members, and for movement in agenerally lateral direction with respect to the press sidewise out ofits operating position at said first support and into its operatingposition at a next successive support along its respective chord, eachsaid press being movable along its respective chord independently of theother, and means for controlling movement of each of the press mountingmeans including means movable therewith for sensing the approach of saidpress to its operating position at a support in advance of its arrivalat its operating position thereby to initiate deceleration of saidmounting means and for sensing the arrival of the press at its operatingposition at the last-said support so as to stop movement of the press atits operating position for driving nailing plates into the wood members.2. Apparatus as set forth in claim 1 wherein said sensing means furtherincludes means for sensing the approach of the press to its operatingposition at each support from one direction along its respective chordand for sensing registration of the press at its operating position ateach support, and means for effecting operation of said sensing means soas to sense the approach of said press to its operating position at eachsupport from the other direction along its respective chord. 3.Apparatus as set forth in claim 2 wherein said sensing means furthercomprises actuating means at each support and switch means carried alongwith the press, said switch means being actuable by said actuating meansas the press approaches its operating position at a support forinitiating deceleration of the press mounting means and being furtheractuable by the actuating means for stopping movement of the pressmounting means with the press in its operating position at one of saidsupports.
 4. Apparatus as set forth in claim 3 wherein said switch meanscomprises a first proximity switch carried along with the press actuableby said actuating means as the press approaches its operating positionat a support for initiating deceleration of the press mounting means anda second proximity switch carried along with the press actuable by saidactuating means for stopping the press mounting means when the press isin its operating position at a support.
 5. Apparatus as set forth inclaim 4 wherein said first and second proximity switches are magneticswitches actuable in response to a magnetic field of a predeterminedstrength, and wherein said actuating means at each support comprises atleast one magnet of sufficient strength to actuate said first and secondproximity switches as they move past the magnet, said magnet beingpositioned on the support and said proximity switches being positionedon the carriage so that said proximity switches pass in close spAcedrelation to the magnet as the press approaches and moves into itsoperating position.
 6. Apparatus as set forth in claim 5 wherein saidactuating means comprises a pair of said magnets, said proximityswitches being spaced apart a predetermined distance and said magnetsbeing spaced on the support a distance corresponding to the spacing ofthe proximity switches so that with the press in its operating positionboth of said switches are actuated by said magnets so as to stop thepress in its operating position and so as to initiate operation of thepress for driving nailing plates into the wood members.
 7. Apparatus asset forth in claim 2 wherein said supporting means comprises a firstframe and a second frame, each frame carrying a series of supports forholding said upper chord members, lower chord members and web members inposition for being secured together by nailing plates so as to fabricatea truss on the supports of each of the frames, said frames beingarranged in end-to-end relation relative to one another so that saidpresses carried by said press mounting means may move along the chordsof respective trusses to be formed on each frame for driving nailingplates into the wood members at the joints of the trusses to befabricated.
 8. Apparatus as set forth in claim 7 wherein the supportsfor the upper chord members and the supports for the lower chord memberson each said frame and arranged in close back-to-back spaced relationand are movable relative to one another longitudinally along theirrespective frame.
 9. Apparatus as set forth in claim 8 wherein eachsupport comprises a vertically disposed plate extending up from saidframe, and wherein said cantilevered means comprises two cantileveredarms in side-by-side spaced relation adapted to support wood members inposition for being secured together by the nailing plates at a locationbetween the arms, said support being adapted for lateral entry of thelower platen of one of the presses from one side or the other thereofbelow said cantilevered arms to its operating position between said armswith the plane of the top surfaces of the arms spaced from the topsurface of the lower platen a distance sufficient to accommodate anailing plate arranged with its teeth pointing upwardly for being driveninto the wood members from below, the cantilever arms being laterallyspaced from one another a distance greater than the width of the lowerplaten of the press for entry of the lower platen of the press betweenthe arms when the lower platen is moved upwardly to drive the nailingplate upwardly into the wood members.
 10. Apparatus as set forth inclaim 8 further comprising track means on each side of said framesextending from the outer end of the first frame to the outer end of thesecond frame, each said press mounting means comprising a power drivencarriage movable in one direction along its respective track means formoving its respective press to its operating position at one of thesupports carried by said first frame into its operating positions ateach successive support along its respective chord of the first frameand movable in the other direction along its respective track means formoving its press to its operating position at one of the supportscarried by the second frame and to its operating positions at eachsuccessive support along its respective chord of said second frame. 11.Apparatus as set forth in claim 10 wherein said first and second framesare arranged in a line and are spaced apart from one another, whereineach of said press carriages is initially positioned at a parkingposition between the frames and wherein, upon the initiation of movementof said carriage in said one direction along its respective track means,said press is automatically moved in said one direction along its trackmeans from its parking position to its operating position at a firstsupport adjacent the inner end of said first frame for driving thenailing plates into the wood members at sAid first support of said firstframe and then is automatically movable to its operating position ateach successive support along its respective chord of said first frameuntil all joints along its respective chord have been secured together,said press carriage then being automatically movable to its parkingposition, and upon initiation of movement of the press carriage in saidother direction along its respective track means, said press isautomatically moved from its parking position to its operating positionat a first support adjacent the inner end of said second frame fordriving nailing plates into the wood members at said first support ofsaid second frame and is automatically moved to its operating positionat each successive support along its respective chord of said secondframe until all joints along its respective chord have been securedtogether, said press carriage then being automatically movable to itsparking position.
 12. Apparatus as set forth in claim 1 wherein saidsupporting means further comprises a frame for carrying a plurality ofsaid supports with the supports for the upper chord members and thesupports for the lower chord members being in close back-to-back spacedrelation and being movable relative to one another longitudinally alongsaid frame.
 13. Apparatus as set forth in claim 12 wherein each supportincludes means for securing it to said frame at any position therealong.14. Apparatus as set forth in claim 13 wherein each support comprises avertically disposed plate extending up from said frame, and wherein saidcantilevered means comprises two cantilevered arms in side-by-sidespaced relation adapted to support wood members in position for beingsecured together by the nailing plates at a location between the arms,said support being adapted for lateral entry of the lower platen of apress from one side or the other thereof below said cantilevered arms toits operating position between said arms with the plane of the topsurfaces of the arms spaced from the top surface of the lower platen adistance sufficient to accommodate a nailing plate arranged with itsteeth pointing upwardly for being driven into the wood members frombelow, the cantilever arms being laterally spaced from one another adistance greater than the width of the lower platen of the press forentry of the lower platen of the press between the arms when the lowerplaten is moved upwardly to drive a nailing plate upwardly into the woodmembers.
 15. Apparatus as set forth in claim 14 further comprising trackmeans on each side of said frame parallel to said upper and lower chordsof the truss to be fabricated, and wherein each said press mountingmeans comprises a power driven carriage movable along a respective trackmeans for moving its press from its operating position at one of saidsupports to its operating position at each successive support along itsrespective chord.
 16. Apparatus as set forth in claim 1, furthercomprising means for lifting a completed truss clear of said support,said lifting means being swingable from a stowed position in which itpermits movement of said press mounting means therepast, and a liftingposition in which it is engageable with one or more wood members of afabricated truss for lifting the completed truss clear of the supports.17. Apparatus as set forth in claim 16 wherein said lifting meansincludes a plurality of rollers engageable with the completed truss toenable rolling of the completed truss from the apparatus when it islifted clear of the supports.
 18. Apparatus as set forth in claim 17wherein said lifting means comprises a plurality of lifting units eachcomprising a mounting bracket adapted to be secured to said main frame,a lift cylinder unit pivotally carried by said bracket for swingingbetween said stowed position and said lifting position, and a swingcylinder unit for effecting swinging of the lift cylinder unit betweenits stowed and lifting positions, said lift cylinder having an armengagEable with members of the completed truss, said arm being movablebetween a lowered retracted position and a raised position in which itis engageable with the completed truss for lifting it clear of thesupports.
 19. Apparatus as set forth in claim 18 wherein said liftingmeans includes means for preventing movement of the lift cylinder unitfrom its lowered retracted position to its raised position until saidswing cylinder unit has fully swung the lift cylinder unit from itsstowed to its lifting position.
 20. Apparatus as set forth in claim 18wherein said arm has a plurality of rollers engageable with various woodmembers of said completed truss enabling rolling of the completed trussfrom the apparatus after it has been lifted clear of the supports. 21.Apparatus as set forth in claim 1 wherein the truss to be fabricated isa flat truss with its upper and lower chords substantially parallel toone another, with the innermost web members of the truss substantiallyperpendicular to the chords, and with others of the webs angled withrespect to the chords and having their ends in contact with the ends ofadjacent webs and with the inner faces of said chord members, saidapparatus further comprising means for clamping said chord members andweb members in position so as to be rigidly secured together by nailingplates, said clamping means comprising a plurality of stops carried bysaid cantilever means engageable by the outer faces of the chord membersthereby to hold the chord members in desired spaced relation, and poweroperated means engageable with the opposed inner faces of said verticalwebs for applying a force thereagainst so as to force all the webmembers into abutting relation with one another and with the inner facesof the chord members from one end of the truss to the other and to holdthe chord members in abutting relation with said stops, and means ateach end of the truss for preventing endwise movement of the outermostweb member relative to the chord members beyond a desired position. 22.Apparatus for fabricating flat wood trusses of the type having lowerchord members, upper chord members and web members extending from thelower chord members to the upper chord members, with said upper andlower chord members substantially parallel to one another, with theinnermost web members substantially perpendicular to the chord membersand with the other of the webs angled with respect to the chords andhaving their ends in contact with the ends of adjacent web members andwith the inner faces of said chord members, said apparatus comprisingmeans for driving nailing plates into two or more of the wood members ofa truss, means for holding the wood members in position for being joinedtogether by said nailing plates including a series of supports, andmeans for clamping said chord members and web members in position so asto be rigidly secured together by nailing plates, said clamping meanscomprising a series of stops carried by said supports engageable by theouter faces of said chord members thereby to hold the chord members indesired spaced relation, and power operated means engageable with thefaces of each of said perpendicular webs facing one another for applyinga force thereagainst so as to force all the web members into abuttingrelation with one another and with the inner faces of the chord membersfrom one end of the truss to the other and to hold the chord members inabutting relation with said stops, and means at each end of the trussfor preventing endwise movement of the outermost web member relative tothe chord members beyond a desired position.
 23. Apparatus forfabricating wood structures, such as trusses of the type having lowerchords, upper chords and web members extending between the chords, saidapparatus utilizing at least one press having an upper platen and alower platen which are relatively movable toward one another for drivingnailing plates into two or more of the wood members at the joints ofsaid truss tHereby to rigidly secure the wood members together, saidapparatus comprising means for holding said wood members in position forbeing secured together by said nailing plates, means mounting the pressfor movement along one chord of the truss to be fabricated in closeproximity to the holding means for driving nailing plates into the woodmember at each joint along said one chord of the truss, and liftingmeans carried by said holding means swingable between a stowed positionsubstantially in the longitudinal vertical centerplane of said holdingmeans in which said press mounting means and said press may movetherepast and a lifting position substantially perpendicular to saidcenterplane and in the path of said press as the latter moves along saidone chord in which said lifting means is engageable with one or more ofthe wood members of the completed truss for lifting the completed trussclear of said holding means.
 24. Apparatus for fabricating woodstructures, such as trusses of the type having lower chords, upperchords and web members extending between the chords, said apparatusutilizing at least one press having an upper platen and a lower platenwhich are relatively movable toward one another for driving nailingplates into two or more of the wood members at the joints of said trussthereby to rigidly secure the wood members together, said apparatuscomprising means constituting supports for holding said wood members inposition for being secured together by said nailing plates, meansmounting the press for movement along one chord of the truss to befabricated in close proximity to the holding means for driving nailingplates into the wood member at each joint along said one chord of thetruss, and lifting means carried by said holding means swingable betweena stowed position in which said press mounting means may move therepastand a lifting position in which it is engageable with one or more of thewood members of the completed truss for lifting the completed trussclear of said supports, said lifting means further comprising aplurality of lifting units each having a mounting bracket adapted to besecured to said frame, a lift cylinder unit pivotally carried by saidbracket for swinging between said stowed position and said liftingposition, and a swing cylinder unit for effecting swinging of the liftcylinder unit between its stowed and lifting positions, said liftcylinder unit having an arm engageable with members of the completedtruss, said arm being movable between a lowered retracted position and araised position in which it is engageable with the completed truss forlifting it clear of the supports.
 25. Apparatus as set forth in claim 24wherein said lifting means includes means for preventing movement of thelift cylinder unit from its lowered retracted position to its raisedposition until said swing cylinder unit has fully swung the liftcylinder unit from its stowed to its lifting position.
 26. Apparatus asset forth in claim 25 wherein said arm has a plurality of rollersengageable with various wood members of said completed truss enablingrolling of the completed truss from the apparatus after it has beenlifted clear of the supports.
 27. Apparatus for fabricating woodstructures, such as trusses of the type having lower chord members,upper chord members and web members extending from the lower chordmembers to the upper chord members, said apparatus comprising a presshaving an upper and a lower platen which are relatively movable towardand away from one another for driving nailing plates into two or more ofthe wood members of a truss from above and below, means for supportingthe wood members which are to be joined together by said nailing plates,said supporting means including a plurality of supports and meanscantilevered relative to each support for holding wood members withclearance therebelow, means mounting the press adjacent one of saidchords for movement of the press from one direction or the other alongits reSpective chord into an operating position at a first support fordriving nailing plates into the wood members, and for movement in agenerally lateral direction with respect to the press sidewise out ofits operating position at said first support and into its operatingposition at a next successive support along its respective chord, meansfor controlling movement of the press mounting means including meansmovable therewith for sensing the approach of said press from onedirection along its respective chord to its operating position at asupport in advance of its arrival at its operating position thereby toinitiate deceleration of said mounting means and for sensing the arrivalof the press at its operating position at the last-said support so as tostop movement of the press as its operating position for driving nailingplates into the wood members, and means for effecting reversal of saidsensing means to sense the approach of said press from the otherdirection along its respective chord to its operating position at asupport in advance of its arrival at its operating position at thelast-said support thereby to initiate deceleration of said mountingmeans and for sensing the arrival of the press at its operating positionat the last-said support so as to stop movement of the press at itsoperating position for driving nailing plates into the wood members. 28.Apparatus for fabricating wood structures, such as trusses of the typehaving lower chord members, upper chord members and web membersextending from the lower chord members to the upper chord members, saidapparatus comprising two presses each having an upper and a lower platenwhich are relatively movable toward and away from one another fordriving nailing plates into two or more of the wood members of a trussfrom above and below, a first and second series of support means forsupporting the wood members which are to be joined together by saidnailing plates, each series including central supporting means andcantilevered means extending laterally outwardly therefrom on oppositesides thereof, said cantilever means being arranged in two rows, one oneach lateral side of the central supporting means for holding memberswith clearance for the lower platens of the presses therebelow, saidfirst and second series being arranged in a line in end-to-end relationrelative to one another, means mounting each of the presses, one presson one side of said line and the other press on the other side of saidline, for movement of the presses independently of one another alongsaid rows, for movement of each press into an operating position at arespective cantilever means so as to drive nailing plates into themembers, and for movement in a generally lateral direction with respectto the press sidewise out of its operating position at said cantilevermeans and into its operating position at a next successive cantilevermeans, said series being spaced apart from one another so that with saidpress mounting means positioned between the first and second series in aparking position, a workman may walk between the ends of either seriesand the press mounting means.
 29. Apparatus as set forth in claim 28further comprising means for controlling movement of each press mountingmeans along its respective said row, operable to stop the press at itsoperating position at each of said cantilever means for driving nailingplates into the members.
 30. Apparatus as set forth in claim 29 whereinsaid cantilever means are arranged in close back-to-back spaced relationand are movable relative to one another longitudinally along said lineto different positions.
 31. Apparatus as set forth in claim 29 whereineach cantilever means comprises a vertically disposed plate extending upfrom said frame, and two cantilevered arms in side-by-side spacedrelation adapted to support wood members in position for being securedtogether by the nailing plates at a location between the arms, saidcantilever means being adapted for latEral entry of the lower platen ofone of the presses from one side or the other thereof below saidcantilevered arms to its operating position between said arms with theplane of the top surfaces of the arms spaced from the top surface of thelower platen a distance sufficient to accommodate a nailing platearranged with its teeth pointing upwardly for being driven into the woodmembers from below, the cantilever arms being laterally spaced from oneanother a distance greater than the width of the lower platen of thepress for entry of the lower platen of the press between the arms whenthe lower platen is moved upwardly to drive the nailing plate upwardlyinto the wood members.
 32. Apparatus as set forth in claim 29 furthercomprising track means on each side of said line extending from theouter end of the first series to the outer end of the second series,each said press mounting means comprising a power driven carriagemovable in one direction along its respective track means for moving itsrespective press to its operating postion at each successive cantilevermeans along each of said series.
 33. Apparatus as set forth in claim 32wherein, with said press carriages initially positioned in their parkingpositions between said series and wherein upon the initiation ofmovement of one of said carriages in said one direction along itsrespective track means, the press of said one carriage is automaticallymoved in said one direction along its track means from its parkingposition to its operation position at a cantilever means adjacent theinner end of said first series for driving nailing plates into the woodmembers at said first cantilever means and then is automatically movableto its operating position at each successive cantilever means along saidfirst series until all joints therealong have been secured together,said press carriage then being automatically movable to its parkingposition, and upon initiation of movement of the press carriage in saidother direction along its respective track means, said press isautomatically moved from its parking position to its operating positionat a first cantilever means adjacent the inner end of said second seriesfor driving nailing plates into the wood members at said firstcantilever means of said second series and is automatically movable toits operating position at each successive cantilever means along saidsecond series until all joints therealong have been secured together,said press carriage then being automatically movable to its parkingposition.
 34. Apparatus as set forth in claim 28 further comprisingmeans for lifting a completed truss from said supporting means of eachof said frames, and means for preventing operation of said lifting meanswhen one of said press mounting means is moved from its parkingposition.